In this paper, we describe CloudCoder, an open platform for creating, assigning, and sharing short programming exercises for a variety of languages (currently C/C++, Java, Python and Ruby). Like other similar systems, CloudCoder is web-based, letting students write code directly in a web browser, click the "submit" button, and receive immediate feedback. Unlike other systems, which tend to be closed, or commercial, or both, CloudCoder is a completely open platform. The code for the system is open-source, and exercises written for CloudCoder may be shared to a central repository under permissive licenses such as Creative Commons BY-SA. Finally, CloudCoder collects detailed data that faculty can use for educational research. We also report on successful pilot studies of CloudCoder at several institutions, and outline research questions we hope to address in future work.

One promising approach to teaching parallel programming is to use high-level parallel programming languages, which handle some of the more mundane details of parallel programming and allow both instructors and students to focus on the main ideas. How does one go about selecting the language to use? We present short descriptions of a variety of languages (Chapel, Cilk, CUDA, Habanero Java, Hadoop, OpenACC, OpenMP and Scala), including our assessment of their strengths and weaknesses, plus some general considerations to keep in mind when teaching parallel programming.

Automatically-tested online programming exercises can be useful in introductory programming courses as self-tests to accompany readings, for in-class assessment, for skills development, and to provide additional practice for students who need it. CloudCoder (http://cloudcoder.org) is an effort to build a community based on an open-source programming exercise system (currently supporting C, Java, and Python) tightly integrated with a repository of freely-redistributable programming exercises written and used by members of the community. The goal of the project is to make programming exercises easy and free to incorporate into any programming course.